JP2901536B2 - Susceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a susceptor for mounting a semiconductor wafer (hereinafter simply referred to as a "wafer") in a CVD process or the like in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art As shown in FIG. 4, a general structure of a mounting type susceptor has a counterbore surface 2 on which a wafer 3 is mounted on a susceptor body. Various types of finishing conditions of the spot facing surface have been proposed. For example, as described in JP-A-2-174116, the center line average roughness Ra <1 μm and the maximum surface roughness Rmax <1
There is a case where a mirror finish is applied to 0 μm, and a case where a surface is intentionally roughened so that the center line average roughness Ra ≧ 1 μm and the maximum surface roughness Rmax ≧ 10 μm.

Here, in the case of mirror finishing, when there is no warpage in the wafer, heat can be efficiently transmitted to the wafer 3 because it is close to surface contact. However, in consideration of the fact that the wafer has a warpage of 100 μm or less as a real problem, the temperature of the contact portion becomes high, and the temperature of the portion not in contact with the susceptor becomes low due to the warpage. In addition, in the case of the sand blasting process, since the contact portion is reduced even when the wafer is not warped, unlike the above-mentioned mirror finish, the heating of the wafer is based on heat transfer,
As a result, when there is a warp, uneven heating in the wafer is reduced.

Here, the less the uneven heating, the more uniform the film thickness at the time of film formation in the CVD process, so that a CVD film that can sufficiently cope with not only the present process but also the next generation multilayer wiring process is obtained. be able to.

[0005]

When a conventional susceptor having a mirror-finished counterbore surface is used, there is a problem that temperature unevenness tends to occur due to wafer warpage. In addition, there is also a problem that the wafer adheres to the counterbore surface due to physical adsorption or electrostatic adsorption, and it becomes difficult to remove the wafer.

In a susceptor having a counterbore surface roughened by sand blasting or the like, the size and shape of the peaks and valleys on the surface are irregular, and the surface roughness is reduced due to wear due to contact with the wafer and cleaning during use. However, there is a problem that the life is short because the contact state with the wafer changes.

SUMMARY OF THE INVENTION An object of the present invention is to provide a susceptor which has less heating unevenness due to the warpage of a wafer, allows easy removal of the wafer, and has an improved life.

[0008]

Means for Solving the Problems The susceptor of the present invention, the recess having a depth which is designed in the same dimensions counterbore surface for location Court the semiconductor wafer are regularly arranged, and the recess
Has a semicircular shape or an inverted triangular shape .

In this case, adjacent recesses are connected to each other.
You may make it .

Further, the concave portion may be formed by mechanical dimple processing, or may be formed by lithography.

Since the counterbore surface has a height difference of at least 10 μm regularly, the wafer is partially floated from the susceptor, so that the wafer can be easily removed.
The uneven heating of the wafer is reduced as in the case of using a susceptor subjected to sandblasting.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1A is a plan view showing an embodiment of the present invention, FIG. 1B is a cross-sectional view taken along line AA of FIG.
FIG. 1C is a partially enlarged plan view of the spot facing portion, and FIG. 1D is a sectional view taken along line BB of FIG. 1C. A counterbore surface 2 on which a wafer 3 is placed is provided on a part of a susceptor body 1 made of a Ni-Cr alloy. The counterbore surface 2 is provided with concave portions 4 having a circular shape in a plane shape at regular intervals by mechanical dimple processing. The depth of the recess 4 is 0.1-0.
They are designed to have the same dimensions of about 5 mm. The width of the projection 5 is, for example, several hundred μm. Here the depth is 0.1-0.5m
The reason for setting m is that if the projections are too high, they will be easily broken during use. On the other hand, if the protrusions are too low, the unevenness is likely to be lost due to wear, and the life cannot be prolonged too much.

When the wafer has no warp, the wafer is slightly floated partially by the convex portion of the dimple. Although the temperature non-uniformity is reduced as in the case of the sand blasted one, it is excellent in that it becomes more regular.
If the wafer has a slight warp, it may be slightly floating from the convex part of the dimple.However, the temperature unevenness is smaller than that of the mirror-finished one, and is almost the same as that of the sand-blasted one. Degree.

Further, the removal of the wafer can be easily performed as in the case of the one subjected to the sand blasting process with a small suction area.

In the case of the sandblasted one, the center line average roughness Ra and the maximum surface roughness Rmax change due to abrasion due to use, so that the contact state with the wafer changes.
In the present embodiment, Ra and Rmax are almost the same, and the contact state hardly changes unless extremely worn, so that the life is extended.

FIG. 2 is a plan view showing a modification of the present embodiment. FIG. 2A shows a case where the recesses 4 are in contact with each other, FIG. 2B shows a case where the recesses are connected to each other to thereby make the protrusions 5 independent, and FIG. 2C shows a case where the recesses are arranged in a staggered manner. Yes, any of these can be used.

FIG. 3 shows a modification of the sectional shape of the concave portion. FIG. 1 shows a stepped cross section of the concave portion.
The shape may be a semicircle as shown in FIG. 3A or an inverted triangle as shown in FIG. These are inferior in life as compared with those in FIG. 1, but have a longer life than those subjected to sandblasting.

The above description has been made on the case where the concave portion is formed by mechanical dimple processing. A recess having a depth of at least 10 μm can also be formed using photolithography technology. In this case, the depth of the concave portion cannot be increased as much as that obtained by machining, so that the life cannot be lengthened much. However, it is clear that the life is prolonged as compared with the sand blasted one.

[0020]

As described above, in the susceptor of the present invention, the recesses designed to have the same dimensions are regularly arranged on the counterbore surface on which the semiconductor wafer is mounted. In addition, there is little heating unevenness due to the warpage of the wafer, and the wafer can be easily removed.
In the case of the sand blasted one, irregularities on the counterbore surface are irregular, and the number and area of contact points with the wafer change greatly due to wear due to use, and the life is short, whereas in the present invention, the irregularities are regular and uniform. Therefore, there is little change in the number of contact points or area due to abrasion, and the life is long.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention (FIG.
(A)), a sectional view taken along the line AA of FIG.
(B)), a partially enlarged plan view of the counterbore surface 2 (FIG. 1 (c))
FIG. 2 is a cross-sectional view taken along line BB of FIG. 1C (FIG. 1D).

FIGS. 2A to 2C are plan views respectively showing three examples of planar shapes according to a modification of the embodiment of the present invention; FIGS.

FIGS. 3A and 3B are cross-sectional views showing two examples of a cross-sectional shape according to a modification of the embodiment of the present invention, separately showing FIGS.

FIG. 4 is a plan view showing a conventional example (FIG. 4A), FIG.
FIG. 4A is a sectional view taken along line AA (FIG. 4B) and a counterbore surface 2.
5 is a partially enlarged sectional view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Susceptor main body 2 Counterbore surface 3 Wafer 4 Concave part 5 Convex part

Claims (4)

(57) [Claims] 1. A recess having the same designed depth is regularly arranged on a counterbore surface on which a semiconductor wafer is placed , and the recess has a semicircular or inverted triangular cross section.
A susceptor having a shape . Wherein this adjacent recesses each other are connected
The susceptor of claim 1, wherein the door. 3. The susceptor according to claim 1, wherein the recess is formed by mechanical dimple processing. 4. The susceptor according to claim 1, wherein the recess is formed by a lithography technique.